Fe(II) bidentate complexes with long-lived triplet states

Abstract

A series of bidentate quinoline/quinoxaline-NHC ligands were coordinated to iron(II) metal centre with the aim of taking advantage of the combined effect of NHC σ-donor and quinoline/quinoxaline Π-acceptors on the excited-state stabilization of the resulting Fe(II) complexes. Excitation of these complexes at 530 nm promoted excited state formation with lifetimes of up to 74 ps. Combined spectroelectrochemistry and transient absorption spectroscopy concluded that a ligand-dependent long-lived MC/MLCT mixed triplet state is at play.